Cylindrical polymer mask and method of fabrication

Abstract

A cylindrical mask may be fabricated using a hollow casting cylinder and a mask cylinder. The casting cylinder has an inner diameter that is larger than the outer diameter of the mask cylinder. The casting and mask cylinders are coaxially assembled and a liquid polymer inserted in a space surrounding the mask cylinder between the inner surface of the casting cylinder and the outer surface of the mask cylinder. After curing the liquid polymer, the casting cylinder is removed. A surface of the cured polymer can be patterned. It is emphasized that this abstract is provided to comply with the rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.

What is claimed is: 
     
         1 . A rotatable mask made by a method comprising:
 an axially symmetric substrate;   a compliant layer on an outer surface of the substrate; and   a seamless pattern on an outer surface of the compliant layer,   wherein the rotatable mask is made by   
       a) coaxially assembling a first casting component inside of a first master mask, wherein the first master mask includes an inner diameter that is larger than an outer diameter of the first casting component, wherein an inner surface of the first master mask includes a pattern; 
       b) depositing a first polymer precursor liquid in a space between an outer surface of the first casting component and the inner surface of the first master mask; 
       c) curing the first polymer precursor liquid to create a first cured polymer, whereby the outer surface of the first cured polymer includes a pattern that corresponds to the pattern of the master mask; 
       d) removing the first casting component from the first cured polymer; 
       e) removing the first cured polymer from the first master mask; 
       f) assembling the first cured polymer inside of a second casting component; 
       g) coaxially assembling a second casting component inside of the first cured polymer, wherein the second casting component has an outer diameter that is smaller than an inner diameter of the first cured polymer; 
       h) depositing a second polymer precursor liquid in a space between an outer surface of the second casting component and an inner surface of the first cured polymer; 
       i) curing the second polymer precursor liquid to create a second cured polymer, whereby the second cured polymer and the first cured polymer together form a compliant layer for the rotatable mask. 
     
     
         2 . A method of making a rotatable mask, the method comprising:
 a) depositing a first polymer precursor liquid on a first surface of a first master mask, wherein the first surface of the first master mask includes a pattern;   b) curing the first polymer precursor liquid to create a first cured polymer, wherein the first cured polymer and the first master mask together form a laminate;   c) configuring a first end of the laminate to have a strip of the first cured polymer missing and a second end of the laminate to have a strip of the first master mask missing;   d) rolling the laminate inside of a first casting component;   e) depositing a second polymer precursor liquid in a gap of the rolled laminate that corresponds to the strip of the first cured polymer;   f) curing the second polymer precursor liquid to form a second cured polymer, whereby the first cured polymer and the second cured polymer together form a compliant layer for the rotatable mask, whereby the outer surface of the compliant layer includes a pattern that corresponds to the pattern of the first master mask.   
     
     
         3 . The method of  claim 2 , further comprising:
 g) removing the first casting component from the laminate after said f).   
     
     
         4 . The method of  claim 2 , further comprising:
 h) removing the first master mask from the compliant layer after said f).   
     
     
         5 . The method of  claim 2 , wherein said c) includes removing a strip of the first cured polymer after said b). 
     
     
         6 . The method of  claim 2 , wherein said c) includes leaving a strip of the first surface of the first master mask exposed when performing said a). 
     
     
         7 . The method of  claim 2 , wherein said d) includes overlapping said ends of the laminate. 
     
     
         8 . The method of  claim 2 , wherein the first end of the laminate is opposite to the second end of the laminate. 
     
     
         9 . The method of  claim 2 , further comprising:
 i) forming the pattern on the first surface of the first master mask before said a).   
     
     
         10 . The method of  claim 9 , wherein said forming the pattern on the first surface of the first master mask includes:
 imprinting a substrate with a second master mask having a pattern, the pattern of the second master mask having a smaller area than the substrate;   successively repeating said imprinting until a desired area of the substrate is patterned, overlapping part of a previously imprinted portion of the substrate with each said successive repetition;   wherein said imprinting the substrate with the second master mask comprises:
 depositing a third polymer precursor liquid; 
 pressing the third polymer precursor liquid between the master mask and the substrate; and 
 curing the third polymer precursor liquid. 
   
     
     
         11 . The method of  claim 2 , wherein the first casting component is a sacrificial casting component. 
     
     
         12 . The method of  claim 3 , wherein the first casting component is a sacrificial casting component, wherein said g) includes fracturing, dissolving, or deflating the first casting component. 
     
     
         13 . The method of  claim 2 , wherein said d) is performed with a second surface of the master mask adjacent to an inner surface of the first casting component. 
     
     
         14 . A method of making a rotatable mask, the method comprising:
 a) coaxially assembling a first casting component inside of a first master mask, wherein the first master mask includes an inner diameter that is larger than an outer diameter of the first casting component, wherein an inner surface of the first master mask includes a pattern;   b) depositing a first polymer precursor liquid in a space between an outer surface of the first casting component and the inner surface of the first master mask;   c) curing the first polymer precursor liquid to create a first cured polymer, whereby the outer surface of the first cured polymer includes a pattern that corresponds to the pattern of the master mask;   d) removing the first casting component from the first cured polymer;   e) removing the first cured polymer from the first master mask;   f) assembling the first cured polymer inside of a second casting component;   g) coaxially assembling a second casting component inside of the first cured polymer, wherein the second casting component has an outer diameter that is smaller than an inner diameter of the first cured polymer;   h) depositing a second polymer precursor liquid in a space between an outer surface of the second casting component and an inner surface of the first cured polymer;   i) curing the second polymer precursor liquid to create a second cured polymer, whereby the second cured polymer and the first cured polymer together form a compliant layer for the rotatable mask.   
     
     
         15 . The method of  claim 14 , further comprising:
 j) covering the outer surface of the first cured polymer with a protective layer before said f).   
     
     
         16 . The method of  claim 14 , wherein the second casting component is a substrate for the rotatable mask. 
     
     
         17 . The method of  claim 14 , wherein said casting components are cylindrically shaped. 
     
     
         18 . The method of  claim 14 , further comprising:
 k) patterning the inner surface of the first master mask before said a), wherein said k) includes:
 forming a structured porous layer over the inner surface of the first master mask, wherein the first master mask is transparent to optical radiation; 
 filling a plurality of pores in the structured porous layer with a filling material; 
 removing portions of the filling material that are not in one of the pores; and 
 forming a plurality of protrusions from the filling material in the pores, wherein the protrusions extend beyond the structured porous layer. 
   
     
     
         19 . The method of  claim 14 , wherein said d) includes fracturing, dissolving, or deflating the first casting component. 
     
     
         20 . A rotatable mask comprising:
 an axially symmetric substrate;   a compliant layer on an outer surface of the substrate; and   a seamless pattern on an outer surface of the compliant layer,   wherein the rotatable mask is made by the method of  claim 2 .